Pt nanoparticles supported on multiwalled carbon nanotubes (MWNT) were synthesized and applied in the catalytic hydrogenation of furfural, the model reaction of mild stabilization of reactive bio-oil. The catalytic properties of the catalysts were modified by changing the surface concentration of oxygen-containing groups (OCGs) of MWNT. Various characterization techniques, including fluorescent labeling, nitrogen physisorption, powder X-ray diffraction, transmission electron microscopy, and in situ DRIFTS analysis, were employed to study both the supports and catalysts. Pt nanoparticles supported on MWNT with high OCGs show high activity and selectivity, attributed to the formation of small Pt particles as a result of the high concentration of OCGs.
An efficient and green method for the modification of lignin by a low transition temperature mixture was used in the synthesis of phenol–furfural resins.
Abstract Catalytic synthesis of C 2 oxygenated compounds from syngas in supercritical cyclohexane was reported in this paper. The effect of the molar ratio of media to feed on the conversion and selectivity was mainly discussed. The results showed that the selectivity of C 2 oxygenated compounds in supercritical cyclo‐hexane was greatly improved, and the by‐products of acetic acid, acetic ester and alkanes were efficiency suppressed. Although the CO conversion was slightly declined, the space‐time yield of C 2 oxygenated compounds basically kept the constant at high media/feed ratio.
Hydrothermal cracking process of residual oil has been developed by our group for many years to upgrade heavy oil feedstock into valuable middle distillate products. It is a tailor-made combined process of thermal cracking and catalytic hydrogenation. This process can suppress gas and toluene insoluble coke yields and promote middle distillate yield comparing with thermal cracking process at the same conversion level. Hydrothermal cracking process was operated at high reaction temperature (693-733K) and medium hydrogen partial pressure (3.0-8.0MPa). Experiments were conducted in batch autoclave reactors and semi-batch reaction systems respectively. Series of catalysts were prepared from different supports (MgO, active carbon, SiO2 and Al2O3) and active metals (Ni, Mo, Co and W, etc.). Feedstock such as bitumen, AR (atmospheric resid) and VR (vacuum resid) were tested. The structure of feedstock and products were characterized by 1H-NMR. The reuse ability and regeneration of catalysts were studied as well. Alumina-supported catalysts showed better performance and regeneration ability. The reaction mechanism of hydrothermal cracking was also studied by model compound and proposed as one consisting of thermal cracking of hydrocarbon molecules via free radical chain reactions and catalytic quench of free radicals by hydrogen.
Deep eutectic solvents based on choline chloride–carboxylic acids, as a low-cost effective bifunctional catalyst, were successfully used to catalyze epoxidation of soybean oil with peroxyformic acid as the oxygen supplier under solvent-free conditions. The influence of reaction temperature and time on the epoxidation process evaluated by 1H nuclear magnetic resonance (NMR) quantitative analysis was extensively investigated. The optimal mild conditions were 50 °C and 8 h for choline chloride–oxalic acid dihydrate with 88.80% conversion of double bonds and a high selectivity of 93.86%. Meanwhile, choline chloride–malonic acid at 50 °C for 10 h exhibited better catalytic performance, 90.87% selectivity versus only 83.52% in the choline chloride–citric acid monohydrate system for 8 h. The epoxy products analyzed simultaneously by 1H NMR and the titration method were characterized in Fourier transform infrared, 13C NMR, and thermogravimetric analysis. The results suggested choline chloride–oxalic acid dihydrate with a favorable recyclability was more efficient for the promotion of epoxidation of soybean oil.
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